Not Applicable
This invention relates to an ink jet printhead chip. More particularly, this invention relates to positioning of ink ejection ports and ink inlets in an ink jet printhead chip.
As set out in the above referenced applications/patents, the Applicant has spent a substantial amount of time and effort in developing printheads that incorporate micro electromechanical system (MEMS)xe2x80x94based components to achieve the ejection of ink necessary for printing.
As a result of the Applicant""s research and development, the Applicant has been able to develop printheads having one or more printhead chips that together incorporate up to 84,000 nozzle arrangements. The Applicant has also developed suitable processor technology that is capable of controlling operation of such printheads. In particular, the processor technology and the printheads are capable of cooperating to generate resolutions of 1600 dpi and higher in some cases. Examples of suitable processor technology are provided in the above referenced patent applications/patents.
The Applicant has overcome substantial difficulties in achieving the necessary ink flow and ink drop separation within the ink jet printheads. A number of printhead chips that the Applicant has developed incorporate nozzle arrangements that each have a nozzle chamber with an ink ejection member positioned in the nozzle chamber. The ink ejection member is then displaceable within the nozzle chamber to eject ink from the nozzle chamber.
An example of such a printhead chip has a nozzle arrangement that is shown schematically with reference numeral 1 in FIG. 1. The nozzle arrangement 1 is positioned on a substrate 2. Nozzle chamber walls 4A and a roof 4B define a nozzle chamber 5 and an ink ejection port 3 in the roof 4B. An ink inlet channel 6 is defined in the substrate 2 and opens into the nozzle chamber 5. The nozzle arrangement 1 includes an ink ejection member 7 that is interposed between the ink ejection port 3 and the ink inlet channel 6. In this embodiment, ink flow is at a premium since the ink inlet channel 6 is as close to the ink ejection port 3 as possible.
Another example of a printhead chip that the Applicant has developed has a number of nozzle arrangements such as the nozzle arrangement 8 indicated schematically in FIG. 2. With reference to FIG. 1, like reference numerals refer to like parts, unless otherwise specified.
Instead of the moving ink ejection member 7, the nozzle chamber walls 4A and the roof 4B of the nozzle arrangement 8 are movable. A static member 9 is positioned in the nozzle chamber 5 so that, when the walls 4A and roof 4B are moved relative to the substrate 2, ink is ejected from the ink ejection port 3.
A particular difficulty with this form of embodiment is associated with achieving the necessary ink ejection pressure within the nozzle chamber 5. A major cause of an undesirable drop in pressure is the flow of ink into the ink inlet channel 6 during displacement of the ink ejection member 7 or the nozzle chamber walls 4A and roof 4B to eject the ink.
In order to address this problem, the Applicant has conceived the present invention.
According to a first aspect of the invention, there is provided a printhead chip for an ink jet printhead, the printhead chip comprising
an elongate substrate; and
a plurality of nozzle arrangements that are positioned along a length of the substrate, the substrate defining a plurality of ink inlet channels, each ink inlet channel being in fluid communication with a respective nozzle arrangement, each nozzle arrangement comprising
nozzle chamber walls and a roof that define a nozzle chamber, the roof defining an ink ejection port;
an ink ejection member that is positioned within the nozzle chamber and is displaceable towards and away from the ink ejection port to eject ink from the nozzle chamber, the nozzle chamber walls and the roof being configured so that the nozzle chamber is generally elongate and has a distal end and an opposed proximal end, the inlet channel of the nozzle chamber being positioned adjacent the proximal end and the ink ejection port being positioned adjacent the distal end; and
an actuator that is mounted on the substrate, the actuator being electrically connected to drive circuitry positioned on the substrate to drive the actuator and the actuator being connected to the ink ejection member to displace the ink ejection member towards and away from the ink ejection port, the nozzle chamber walls and roof being dimensioned so that a fluid flow path defined between the ink ejection port and the ink inlet channel is configured to retard ink flow between the ink ejection port and the ink inlet channel during ejection of ink from the ink ejection port.
According to a second aspect of the invention, there is provided a printhead chip for an ink jet printhead, the printhead chip comprising
an elongate substrate; and
a plurality of nozzle arrangements that are positioned along a length of the substrate, the substrate defining a plurality of ink inlet channels, each ink inlet channel being in fluid communication with a respective nozzle arrangement, each nozzle arrangement comprising.
a nozzle chamber structure that at least partially defines a nozzle chamber, the nozzle chamber structure having a roof that defines an ink ejection port, the nozzle chamber structure being configured so that the nozzle chamber is generally a elongate and has a distal end and an opposed proximal end, the ink inlet channel of the nozzle arrangement being positioned adjacent the proximal end and the ink ejection port being positioned adjacent the distal end;
an actuator that is mounted on the substrate, the actuator being electrically connected to drive circuitry positioned on the substrate to drive the actuator and the actuator being connected to the nozzle chamber structure at the proximal end of the nozzle chamber so that the actuator can displace the nozzle chamber structure towards and away from the substrate; and
a static member that is mounted on the substrate intermediate the ink ejection port and the substrate so that displacement of the structure towards and away from the substrate results in the ejection of a drop of ink from the ink ejection port, the structure being dimensioned so that a fluid flow path defined between the ink ejection port and the ink inlet channel is configured to retard a flow of ink from the ink ejection port to the ink inlet channel when the structure is displaced towards the substrate.
The invention is now described, by way of example, with reference to the accompanying drawings. The following description is not intended to limit the broad scope of the above summary.